Regular flooding has plagued the road near the entrance to Astley Park, with police forced to close it twice in less than a week following the heavy rain brought by Storm Christoph.
Fire crews have been called to the scene to try and pump out some of the floodwater, but the road remains closed after being deemed unsafe.
Chorley Council workers have also resumed efforts to pump out the water, but it is not yet known when the road will be reopened.
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But the council has now had to issue a warning to residents following a number of instances of people "floating on the floodwater using pool inflatables."
A Chorley Council spokesman said: "Please can we remind people not to enter the floodwater in Astley Park."
"We have instances of people floating on the water using inflatables."
Floodwater is dangerous and dirty, potentially carrying hundreds of harmful chemicals, including fuel, anti-freeze, dead and decaying animals and runoff from farms and pastures that can contain pesticides, herbicides, fertilizers and animal waste.
As well as unpleasant chemicals, floodwater also picks up everything in its path. This can include sharp objects such as broken glass, barbed wire, tree branches and metal fragments.
Hidden rocks, ditches and potholes may also cause you to lose your footing and strain a muscle or twist an ankle.
"It is extremely dangerous and it will put unnecessary strain on the emergency services if an accident occurs," the spokesman added.
Pictures from the scene show the Grade-II listed Ackhurst Lodge nearly fully submerged by the floodwater, prompting concerns from residents who fear the historic building is at risk of permanent damage.
But a solution to the flooding is now in the works, with the council confirming the blockage is being caused by logs that have fallen into the river during tree felling along the River Chor, which is now restricting water flow through the culvert under Southport Road.
It added plans are being drawn up to remove the blockage as soon as the water levels subside and workers can gain safe access to the culvert.
A spokesman for Lancashire County Council said: "We have been working closely with Chorley Council to pump the water away to try to prevent any further damage, and the water level is now dropping.
"Once the water level has reduced enough to allow access we will need to assess the damage and determine what actions will be required before the road can be fully reopened."
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